A ? for those that have their skimmer suck outside air.
- Thread starter Fluids&Jelly
- Start date
Well currently I just leave the door open to the sub basement, so it is getting some passive ventilation, with the rest of the house, that way.
The reason I was contemplating the outside air for the skimmer was to, 1.counter act supressed ph due to CO2 build-up in a new house and
2. to muffle the loud sucking air sound of the skimmer.
I was just curious as to what would be required (as in what do I need to control) if I plumbed a fresh outside air line to my skimmer.
The reason I was contemplating the outside air for the skimmer was to, 1.counter act supressed ph due to CO2 build-up in a new house and
2. to muffle the loud sucking air sound of the skimmer.
I was just curious as to what would be required (as in what do I need to control) if I plumbed a fresh outside air line to my skimmer.
hi.
The amount of air sucked by the the skimmer is such a small quantity that the temperature issue is not something to be concerned.
A 1 HP air conditioner can cool a pretty large room quickly, while a medium sized aquarium (120-240gal) needs a much larger chiller to do the same task. This is because the specific heat of air is much smaller than water, and if you want to use frigid air to cool your tank water, it will be very difficult to do so.
So just make sure the air intake is not blocked or near the exhaust of your car or something like that.
The amount of air sucked by the the skimmer is such a small quantity that the temperature issue is not something to be concerned.
A 1 HP air conditioner can cool a pretty large room quickly, while a medium sized aquarium (120-240gal) needs a much larger chiller to do the same task. This is because the specific heat of air is much smaller than water, and if you want to use frigid air to cool your tank water, it will be very difficult to do so.
So just make sure the air intake is not blocked or near the exhaust of your car or something like that.
mr.Ing
hey.
not to make a contention regarding cool air-(though i specifically was thinking about below freezing air in the winter travelling a relatively short distance to the skimmer possibly cooling the tank)
a question on the chiller/ac issue:
is a chiller as good as, or better than, a chiller in its ability to transfer heat?
the reason i ask is that i see lots of chillers placed near the tank, in the same room as the tank.doesn't look like there's anywhere for alot of the heat to go-while an a/c pumps it directly outside a room.could this be part of the reason why a larger hp chiller is usually needed?
hey.
not to make a contention regarding cool air-(though i specifically was thinking about below freezing air in the winter travelling a relatively short distance to the skimmer possibly cooling the tank)
a question on the chiller/ac issue:
is a chiller as good as, or better than, a chiller in its ability to transfer heat?
the reason i ask is that i see lots of chillers placed near the tank, in the same room as the tank.doesn't look like there's anywhere for alot of the heat to go-while an a/c pumps it directly outside a room.could this be part of the reason why a larger hp chiller is usually needed?
vitz:
Don't really understand your question, so let me know if you have the same feeling with this post...
The reason for a higher power chiller with the same volume (16 cubic feet tank and 16 cubic feet refrigator, for example, ~ 120 gal) is because it is much easier to cool the air than the water. If the thermostat is accurate to maintain the temperature within +/- 1 F, the amount of energy it takes to remove 1 F of heat from 16 CF of air is much less than the same amount of water. FYI, if my temperature conversion is correct, there are ~200 kCal of heat in 16 CF of water, for dry air, the specific heat is about half of water with the same weight, but consider the weight ratio of air/water, the amount of heat in air is around 500 X less. With humid air, the specific heat is higher, but within the same magnitude. So it takes much less energy (less powerful compressor) to cool the air than a water tank.
Regarding the chill-in-the-same-room issue, although it is not a good thing to do, but with the space limitation, it is often not possible to locate the chiller in a separate room. The drop -in type chiller only come with a short probe, while most people don't want to drill holes on the wall if they have a in-line chiller that can be in a separate room. Minority of reefer have a remotely located chiller, some even outside.
Even with the chiller in the same room, it is possible to cool the tank as long as the heat transfer between the room air and the tank water is less than the heat removed by the chiller to the room air via the compressor. Acrylic tank is better isolator of heat and it helps somewhat. It just takes more energy to run the chiller in a hot room, that's all.
Hack! If I have the money to buy a chiller, and run a reef, what do I care about that extra $100 a month in electric bill :wink:
Don't really understand your question, so let me know if you have the same feeling with this post...
The reason for a higher power chiller with the same volume (16 cubic feet tank and 16 cubic feet refrigator, for example, ~ 120 gal) is because it is much easier to cool the air than the water. If the thermostat is accurate to maintain the temperature within +/- 1 F, the amount of energy it takes to remove 1 F of heat from 16 CF of air is much less than the same amount of water. FYI, if my temperature conversion is correct, there are ~200 kCal of heat in 16 CF of water, for dry air, the specific heat is about half of water with the same weight, but consider the weight ratio of air/water, the amount of heat in air is around 500 X less. With humid air, the specific heat is higher, but within the same magnitude. So it takes much less energy (less powerful compressor) to cool the air than a water tank.
Regarding the chill-in-the-same-room issue, although it is not a good thing to do, but with the space limitation, it is often not possible to locate the chiller in a separate room. The drop -in type chiller only come with a short probe, while most people don't want to drill holes on the wall if they have a in-line chiller that can be in a separate room. Minority of reefer have a remotely located chiller, some even outside.
Even with the chiller in the same room, it is possible to cool the tank as long as the heat transfer between the room air and the tank water is less than the heat removed by the chiller to the room air via the compressor. Acrylic tank is better isolator of heat and it helps somewhat. It just takes more energy to run the chiller in a hot room, that's all.
Hack! If I have the money to buy a chiller, and run a reef, what do I care about that extra $100 a month in electric bill :wink:
Just an example to clarify what Mr Ing is stating.
When build a campfire to boil water the air around the fire heats up much quicker then the water in the pot. The same is true when during the winter. The air gets cold before the water in the pond freezes. Water will take more energy to cool then will air.
When build a campfire to boil water the air around the fire heats up much quicker then the water in the pot. The same is true when during the winter. The air gets cold before the water in the pond freezes. Water will take more energy to cool then will air.
Perhaps I don't agree with your logic.
The cooler the air in your apartment the cooler your tank. Your tank *always will* try to become the same temp as the surrounding air. Also the effects of an air conditioner are to lower the relative humidity in your room, thus increasing the cooling effects due to evaporation from your tank.
I would recommend that everyone/anyone buy an A/C over a chiller! It's a much better investment and will keep you cool as well.
-Nathan
The cooler the air in your apartment the cooler your tank. Your tank *always will* try to become the same temp as the surrounding air. Also the effects of an air conditioner are to lower the relative humidity in your room, thus increasing the cooling effects due to evaporation from your tank.
I would recommend that everyone/anyone buy an A/C over a chiller! It's a much better investment and will keep you cool as well.
-Nathan
Nathan,
We were answering the following question.
Mr Ing and I (in my example, were answering that question.
A 5000 BTU/hr (~2hp) window Air Conditioner is rated for a 150 sq ft room. If you filled that same room up with water (salt water even makes it worse) the same Air Conditioner could not pull down the temperature at the same rate. Being that Air can transfer heat much better then water.
The inital question of using outside air for your skimmer. The outside air temperature will be negligable. Other factors would be more of a concern. Dust/lawn chemicals/bugs/etc.
If the question was which would be better to buy AC or Chiller then. I agree that an AC would be better for the reasons you state.
We were answering the following question.
vitz":39ce15xq said:
Mr Ing and I (in my example, were answering that question.
A 5000 BTU/hr (~2hp) window Air Conditioner is rated for a 150 sq ft room. If you filled that same room up with water (salt water even makes it worse) the same Air Conditioner could not pull down the temperature at the same rate. Being that Air can transfer heat much better then water.
The inital question of using outside air for your skimmer. The outside air temperature will be negligable. Other factors would be more of a concern. Dust/lawn chemicals/bugs/etc.
If the question was which would be better to buy AC or Chiller then. I agree that an AC would be better for the reasons you state.
ok,then maybe this question will show my lack of understanding...
why wouldn't very cold air, introduced with a large surface area/water ratio (via the micro bubbles of a skimmer)-not cool down a tank? isn't this akin to a room a/c?
just seems to me (entirely intuitively, i'll admit :wink: ) that air at 40 deg.F pumped into a skimmer will cool down a tank quite abit.
which is why i suggested that as long as the air can warm to ambient house temp before it reaches the skimmer, there wouldn't be a problem.
your thoughts please...
why wouldn't very cold air, introduced with a large surface area/water ratio (via the micro bubbles of a skimmer)-not cool down a tank? isn't this akin to a room a/c?
just seems to me (entirely intuitively, i'll admit :wink: ) that air at 40 deg.F pumped into a skimmer will cool down a tank quite abit.
which is why i suggested that as long as the air can warm to ambient house temp before it reaches the skimmer, there wouldn't be a problem.
your thoughts please...
hi.
First of all, I want to say that I may not agree with some of you regarding AC/chiller choice, depends on setup.
As I said already, the heat capacity of air is so small that it will take 500X more energy to cool air than same amount of water. So assume the heat exchange between the air and water is perfect (nothing in practical thermodynamic is perfect, but let's say that the surface area of the bubble is infinite, and the heat transfer between air bubble and the tank water is perfect), then it will take 500 gal of 0F dry air to cool 1 gal of tank water from 80F to 40F. Or the same amount of air to cool 8 gal of water to 75F.
Now, do you know how many gal of air does your skimmer suck in per day? For non-commerical skimmer, it is about in the magnitude of gallon per hour. So compare to the size of you tank, the amount of cooling in a perfect situation is almost negliectible.
On a lighter note, did anybody heard about the myth of a newbie reefer who don't want to buy a water heater, and use a hair dryer blowing hot air at water surface to keep his/her tank warm during the winter? Now hair dryer will do a better job in heating up tank water than chilly air from outside, so please don't laugh at this.
Now regarding the AC/Chiller issue. If the chiller is remotely mounted, meaning that the hot air from chiller is direct outside instead of recirculated within the room, then a chiller will be more efficient in cooling a tank than a room AC. If the reefer want to enjoy comfortable room temperature while in the room, then it maybe a good investiment to get a room AC instead of chiller alone. This assumes that the "value" of the comfort is more than the extra energy that a room AC uses. Extra energy will needed because of the inefficiency of heat transfer between room air and the tank water, as well as heat gain due to opening door/window and heat transfer thru house wall and others.
Another exception is if the chiller can not be setup in such a way that the heat can be transfer away from the room's air. This is like running a portable AC in the middle of a room, with cool air coming from one side, and hot air coming from the opposite side, essentially cancel out the cooling affect while adding more net heat to the room. For chiller, this is not so bad, because the tank wall insolated the water from the air a little. See the hair dryer myth above. So it is not so bad as some people feel.
Other issue is that when sizing a room AC, you have to consider the extra heat from the tank. An room AC work for a normal 200 sqft living room will not work on a fish room of the same size with 13 240 gal tanks, for example. All in all, there are so many issues that it is impossible to give fool-proof recommendation without knowing the preference of the reefer and other constraints.
First of all, I want to say that I may not agree with some of you regarding AC/chiller choice, depends on setup.
As I said already, the heat capacity of air is so small that it will take 500X more energy to cool air than same amount of water. So assume the heat exchange between the air and water is perfect (nothing in practical thermodynamic is perfect, but let's say that the surface area of the bubble is infinite, and the heat transfer between air bubble and the tank water is perfect), then it will take 500 gal of 0F dry air to cool 1 gal of tank water from 80F to 40F. Or the same amount of air to cool 8 gal of water to 75F.
Now, do you know how many gal of air does your skimmer suck in per day? For non-commerical skimmer, it is about in the magnitude of gallon per hour. So compare to the size of you tank, the amount of cooling in a perfect situation is almost negliectible.
On a lighter note, did anybody heard about the myth of a newbie reefer who don't want to buy a water heater, and use a hair dryer blowing hot air at water surface to keep his/her tank warm during the winter? Now hair dryer will do a better job in heating up tank water than chilly air from outside, so please don't laugh at this.
Now regarding the AC/Chiller issue. If the chiller is remotely mounted, meaning that the hot air from chiller is direct outside instead of recirculated within the room, then a chiller will be more efficient in cooling a tank than a room AC. If the reefer want to enjoy comfortable room temperature while in the room, then it maybe a good investiment to get a room AC instead of chiller alone. This assumes that the "value" of the comfort is more than the extra energy that a room AC uses. Extra energy will needed because of the inefficiency of heat transfer between room air and the tank water, as well as heat gain due to opening door/window and heat transfer thru house wall and others.
Another exception is if the chiller can not be setup in such a way that the heat can be transfer away from the room's air. This is like running a portable AC in the middle of a room, with cool air coming from one side, and hot air coming from the opposite side, essentially cancel out the cooling affect while adding more net heat to the room. For chiller, this is not so bad, because the tank wall insolated the water from the air a little. See the hair dryer myth above. So it is not so bad as some people feel.
Other issue is that when sizing a room AC, you have to consider the extra heat from the tank. An room AC work for a normal 200 sqft living room will not work on a fish room of the same size with 13 240 gal tanks, for example. All in all, there are so many issues that it is impossible to give fool-proof recommendation without knowing the preference of the reefer and other constraints.
O P Ing":2itc3h1k said:
Actualy the Specific heat capacity of air is only 1/4 of water.. not 1/500th so you would only need 4 gal of air to match 1 gal of water.. if it was as far off as you stated refrigerators, ACs, and other air coolers would not work because one 1 lb of 60 dregree hamburger would heat the fridge up to 59 degrees instead of being cooled off.
Ac's do work well for controling a tank temp.. you simpaly make the room temp about the same or a little cooler than you want the tank and if will eventualy equalize to that temp.. the reason people want chillers is that you can have your room temp different than your tank Temp.
Steve
a 50 gal. tank at 80deg.F. in a room at 75deg.F.with one gallon of 40deg.F air/hr. piped in through the skimmer(continuously):
if the room is kept at 75deg.F-will the tank cool down to below the temp of the room?(assume the tank does not have a heater in it, or halide lights :wink: ).
if the room is kept at 75deg.F-will the tank cool down to below the temp of the room?(assume the tank does not have a heater in it, or halide lights :wink: ).
hi.
You guys are giving me hard time! :twisted: Anyway...
CRC Handbook of Chem. and Phys., 72nd edition. pg. 6-1:
Cp of air @ 1 bar, 300 K is 1.007 J/g K
same reference, pg 6-9:
Cp of water @ 1 bar, 30C (~300K) is 4.1784 J/g K
dry air has a slighly lower Cp value, and please take notice of the unit of Cp (i.e., j/g K) and see the following quote:
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